1. Delayed ligation of the umbilical cord;Ballentine;Pennsylvania M. J.,1947
2. Obstetrical Practice;Beck,1955
3. Blood volume of newborn infant in relation to early and late clamping of umbilical cord;Demarsh;Am. J. Dis. Child.,1942
4. The importance of gravity in delayed ligation of the umbilical cord;Duckman;Am. J. Obst. & Gynec.,1953
5. Williams Obstetrics;Eastman,1956